1. Technical Field
The present invention relates to an electronic device and an electromagnetic wave timepiece which receive a communication electromagnetic wave including time information.
2. Related Art
In an electromagnetic wave timepiece which receives time signal transmitted by means of an electromagnetic wave, and displays accurate time information, in addition to a method which receives a standard frequency and time signal, in a low frequency band, transmitted from a ground base station, or a time signal, in an ultrahigh frequency band, transmitted from a GPS (Global Positioning System) satellite, recently, as described in JP-A-2000-321383, an electromagnetic wave timepiece has been proposed which receives a time signal, included in an electromagnetic wave in an ultrahigh frequency band, which is CDMA (Code Division Multiple Access) modulated and transmitted for the purpose of mobile communication, corrects a self-measured time, and displays an accurate time. It has been known that this kind of electromagnetic wave in the ultrahigh frequency band, as it is relayed far and wide by various kinds of repeater, can be received in a good condition even at various movement destinations, such as an inside of a building or underground, in comparison with the standard frequency and time signal in the low frequency band, and the electromagnetic wave from the GPS satellite. Also, JP-A-2001-166071 has proposed an electromagnetic wave timepiece which generates electric power by converting kinetic energy generated by means of a rotation of a rotating spindle into electric energy, and accumulates and uses the generated electric power, and which stops a reception operation during the electric power generation in order to avoid a decrease in an electromagnetic wave reception sensitivity due to a noise occurring when generating the electric power.
The heretofore described kinds of electromagnetic wave timepiece often being used worn on an arm in a mode of a wrist watch, in order to realize a reduction in a size and a weight, a small battery is incorporated as a power supply. However, there has been the following problem. That is, because there are large amounts of consumption current in an operation of receiving the electromagnetic wave and acquiring the time information, and in an operation of driving a drive unit in order to update a display time, in the event that these two operations are executed overlapping temporarily, as the consumption current increases abruptly, a capacity of the battery decreasing remarkably, it is impossible to efficiently consume electric power which can be supplied from the battery. Furthermore, recently, there has been the following problem. That is, as the electromagnetic wave timepiece often receives and corrects the electromagnetic wave in order to reduce an error in the display time as much as possible, for example, in the event that the electromagnetic wave is received while the drive unit of the electromagnetic wave timepiece is in the process of driving a second hand, a noise arises from a drive electric circuit or the like, and the electromagnetic wave reception sensitivity decreases due to this noise.